TY - JOUR T1 - Revisiting screening for type 2 diabetes mellitus: the case for and against using HbA1c JF - British Journal of General Practice JO - Br J Gen Pract SP - e278 LP - e280 DO - 10.3399/bjgp15X684637 VL - 65 IS - 633 AU - Fahmy WF Hanna AU - Veronica Wilkie AU - Basil G Issa AU - Anthony A Fryer Y1 - 2015/04/01 UR - http://bjgp.org/content/65/633/e278.abstract N2 - Type 2 diabetes mellitus is a major cause of morbidity and premature mortality in the Western world. It is responsible for about 10% of the NHS spend (about £286/second in the UK). Of those diagnosed with type 2 diabetes, 25% are thought already to have evidence of complications indicating that the disease has been present for 4–7 years.1 Where people have been diagnosed with a ‘pre-diabetes’ condition, such as impaired fasting glycaemia or impaired glucose tolerance (IGT), a proportion still demonstrate evidence of micro- and macrovascular complications. Research has led to the hypothesis that early detection, particularly in the early stages of the disease, can reduce the incidence of complications.Many centres and professional bodies have adopted the recent guidance to utilise glycosylated haemoglobin (HbA1c) as a diagnostic tool for diabetes mellitus. Although HbA1c offers much potential in this regard, it is not yet entirely clear how it should be used in clinical practice in the context of existing tests.Evidence of microvascular and macrovascular disease is present in the 25% of newly-diagnosed cases of type 2 diabetes mellitus and also in those thought to be in a pre-diabetes state, therefore this has led to difficulties in deciding the cut-off levels for a clear diagnosis (Table 1).View this table:In this windowIn a new windowTable 1. Diagnostic tests for diabetes with their cut-off valuesThe random plasma glucose (PG) sample is cheap and easy to do, and the diagnosis of type 2 diabetes mellitus in screened patients is conclusive if the values are ≥11.1 mmol/L. Lower values are more difficult to interpret. Research evidence correlating a diagnosis of diabetes, using a random glucose level, … ER -